Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating

The role that the supporting anion has on the stability, structure, and catalytic performance, in solid-state molecular organometallic systems (SMOM) based upon [Rh(Cy2PCH2CH2PCy2)(η2η2-NBD)][BArX4], [1-NBD][BArX4], is reported (X = Cl, F, H; NBD = norbornadiene). The tetra-aryl borate anion is systematically varied at the 3,5-position, ArX= 3,5-X2C6H3, and the stability and structure in the solid-state compared with the previously reported [1-NBD][BArCF34] complex. Single-crystal X-ray crystallography shows that the three complexes have different packing motifs, in which the cation sits on the shared face of two parallelepipeds for [1-NBD][BArCl4], is surrounded by eight anions in a gyrobifastigium arrangement for [1-NBD][BArF4], or the six anions show an octahedral cage arrangement in [1-NBD][BArH4], similar to that of [1-NBD][BArCF34]. C–X···X–C contacts, commonly encountered in crystal-engineering, are suggested to be important in determining structure. Addition of H2 in a solid/gas reaction affords t...